Air directing device for gun-type fuel oil burners



1951 c. M. GRESSLEY 2,569,754

AIR DIRECTING DEVICE FDR GUN-TYPE FUEL OIL BURNERS Filed May 27, 1949 11INVENTOR. 5 CBHFKRLE MFKHL N RE LEY 7 7 x25. Q- BY ATTORNEY PatentedOct. 2, 1951 AIR DIBECTING DEVICE FOR GUN-TYPE FUEL OIL BURNE CharlesMahlon Gressleh Allegheny County,

search & Development Company, a corporation of Delaware HarrisonTownship. assignor to Gulf Be- Pifllbllrh,

Application May 27, 1949, Serial No. 95,769 1 Claim. 158-15) Thisinvention relates to an air directing device for gun type fuel oilburners, and more particularly to a device for attachment to the nozzleend of the air blast tube of a gun type fuel oil burner which isdesigned to burn atomized fuel.

In the combustion of atomized fuel in gun type fuel burners some meansis necessary to provide a supply of air or oxygen to the atomized fuelin order to produce combustion of said fuel. Heretofore the art hasresorted to devices which produce a turbulent cone of air around theatomized fuel spray. employed by the prior art in that it causes a morethorough mixing of the air with atomized fuel and a greater penetrationby the air of the fuel spray cone.

The principal object of my invention is to provide a device which willproduce improved combustion in gun type fuel burners.

A further object is to provide a device for mixing air with the fuelspray, said device requiring no moving parts.

Another object of my invention is to provide a device which will notonly direct air to the fuel spray but will also serve to confine theflame and prevent impingement thereof on the combustion chamber walls.

A still further object is to provide an air directing means which willallow the fuel nozzle to keep relatively cool thereby minimizingclogging thereof. Other objects will appear hereinafter.

These objects are accomplished by employing my invention in a fuelburner, said invention comprising a plate having a relatively largecentral circular orifice, a plurality of rows of smaller orificessurrounding said central orifice and a plurality of elongated peripheralslots located near the outer edge of said plate. The purpose of thisplate is to break up the supply of air into a plurality of jets. Thesejets of air are then mixed with the previously atomized fuel.

In the drawings like characters of reference refer to like elements.

Figure l is a side elevation, partly broken away, of a complete furnaceemploying a gun type fuel burner and shows the relative location of itsvarious parts including my improved air injector.

Figure 2 is an end elevation of my air direction means when attached tothe nozzle end of the air blast tube.

Figure 3 is a sectional view of Figure 2 taken along the line 3-3.

Taking up the drawings in detail, in Figure 1 My device differs fromthose the numeral I refers to my improved air directing plate, which islocated in front of and. spaced apart from atomizing nozzle 2. Atomizingnozzle 2 with its fuel supply tube is located centrally of air blasttube 3. The air blower is denoted by numeral 4 and is located at therear end of air blast tube 3. Numeral Ii designates the main body of thefurnace while numeral 5 refers to the combustion chamber proper.

In Figure 2, numeral I again points out the entire air directing means.Numeral 2 designates the atomizing nozzle and shows its positionrelative to the large central circular opening 1. Numeral 8 refers toone of the plurality of smaller circular orifices which surround centralopening 1, said smaller circular orifices being arranged in rowsconcentric to circular opening I. Numeral 9 points out one of theequally spaced relatively elongated slots which are located near theperiphery of plate I.

In Figure 3, the location of my improved air injecting device I withrespect to that of air blast tube 3, and that of atomizing nozzle 2 isclearly brought out. In this figure, numeral Ill designates a sleeveportion attached to the rear face of plate I. Sleeve I I is adapted toengage air blast tube 3. Sleeve ll and attached plate I are held inplace by means of screws II and II.

The operation of my device is as follows: the air from blower 4 travelsdown air blast tube 3 to plate I. The relatively large stream of air isbroken up at this point into numerous jets of shapes corresponding tothe configuration of the various orifices in the plate.

Since the air stream is more confined by the orifices of the plate thanby the air blast tube, the speed of the individual jets is somewhatgreater than the speed of the air stream in the air blast tube.

The large blast of air passing through the center hole 1 performs thefunction of creating an initial supply of oxygen for the combustion ofthe atomized fuel emerging from the nozzle 2.

In addition this center air blast serves to keep the atomizing nozzle 2relatively cool and minimizes clogging thereof by reducing the amount ofheat reflected on said nozzle 2 from the flame and from the combustionchamber 5.

The smaller orifices, surrounding the large central orifice andexemplified by orifice 8, direct a plurality of high velocity jets ofair into the partially burned fuel spray and wash away combustion gasesfrom the unburned fuel, while at the same time furnishing additionaloxygen for further combustion.

The peripheral slot like openings exemplified by orifice 8 direct morestreams of air which perform th same washing and mixing action asproduced by the air jets emitted from the smaller orifices and inaddition cause the flame to be confined and prevent impingement thereofon the walls of the combustion chamber 5. These peripheral slots areessential in my invention for the production of optimum results. Testswere carried out using plates both with and without said peripheralslots and substantially improved combustion efiiciency was obtained bythe use of the plate having the peripheral slots.

As a modification of my invention, 1 contemplate the use of peripheralslots which are not necessarily equally spaced. As a furthermodification the large central orifice and the surrounding smallerorifices need not necessarily be circular. Circular orifices arepreferred, however, for convenience of manufacture. Furthermore, plate Ineed not necessarily be fiat. A slight concavity or convexity wouldproduce equally improved results without departing from the spirit of myinvention. As a still further modifl cation, I contemplate the use offastening means other than sleeve l and screws H and I2. Any equivalentmeans which will perform th fastening function may be used. In additionthe plurality of smaller orifices exemplified in the drawing by orifice8 need not be arranged in rows absolutely concentric to large circularorifice I since slight deviations would produce substantially identicalresults. I do not intend to be limited to the use of four peripheralslots as illustrated. A plate having six such slots, for' fuel, whethersaid fuel is powdered or liquid.

The principal. advantage produced by my invention is that of improvedcombustion efilciency. A further advantage of my device is that itemploys no moving parts. Consequently, there are no problems of wear andpart replacement. A further advantage of my invention is that it reducesclogging of the atomizing nozzle thereby rendering unnecessary frequentcleaning of the said nozzle.

What I claim is:

In combination with a fuel burner having an airblast tube and a burnernozzle located centrally and axially adjacent the discharge end thereof,an air directing device mounted over the nozzle end of said air blasttube and spaced outwardly from said burner nozzle. said air directingdevice comprising a plate-like member having a relatively large centralopening surrounded by a circular series of widely spaced smalleropenings, spaced arcuate slots adjacent the periphery of said member, ofa curvature centered on the axis of ,said central opening, andconcentric rows of closely spaced smaller openings located radiallyoutward of said circular series of widely spaced openings and betweensaid spaced arcuate slots, in groups alternating with said arcuateslotscircumferentially of said member.

' CHARLES MAHLON GRESSLEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

